1. Technical Field
The present invention relates to a speech processing systems and, more particularly, to a method for automatically punctuating a speech utterance in a continuous speech recognition system.
2. Discussion of Related Prior Art
In everyday speech, punctuation is not pronounced. However, in conventional speech recognition systems, in order to insert punctuation marks in the transcribed text, punctuation must be explicitly pronounced by name (e.g., PERIOD, COMMA, COLON, etc.). Accordingly, some users of conventional speech recognition systems find the requirement of pronouncing punctuation unnatural, and disruptive to the thinking process. However, the input of natural speech into a speech recognition system without pronounced punctuation results in an output without punctuation and also, an increased error rate. The latter occurs because punctuation is usually part of the language model. Thus, it would be highly desirable for punctuation to be automatically inserted.
Automatic insertion of punctuation would be important in many situations. One such situation is when spontaneous speech recognition is used to generate an original composition based on new ideas (known as free-hand composing). During free-hand composing, an uninterrupted thought process focused on the subject of the new ideas is desired. Accordingly, the requirement of simultaneously providing punctuation may be seen as an impediment to the flow of ideas since the correct use of punctuation requires a significant degree of thought (see, for example, "The Random House Guide to Grammar, Usage, and Punctuation", by Laurie Rozakis, Random House, 1991; "Chicago Manual of Style", 14th Edition, University of Chicago Press, 1993). Thus, punctuation is usually not expressed along with the original ideas during free-hand composing. Instead, and more naturally, the ideas are first dictated and then, punctuation is added. However, the automatic insertion of punctuation during free-hand composing would lessen the amount of editing required in the editing stage, and make the raw script more easily readable.
The automatic insertion of punctuation would also be important in situations such as decoding radio or television broadcasts, or public speeches. This is because, understandably, pronounced punctuation is not desirable or permissible in such situations.
In some countries (or for some languages), pronouncing the corresponding various types of punctuation marks is difficult (e.g., Chinese and Spanish), and often people do not have experience in pronouncing punctuation (compared to the United States, where dictation is widely used).
Thus, it would be desirable and highly advantageous to provide a method for automatically punctuating a speech utterance in a continuous speech recognition system.